The conflict in Donbas will not end until there is a regime change in Kyiv. As long as the nationalists rule Ukraine there can be no change in the situation. But whoever wins the Ukrainian elections will continue to serve the interests of the US. Ukraine will be torn into two parts, a Western and an Eastern state. The Donbas will not likely ever return to Ukraine; it has developed its own managerial system, culture and economy. The “Donbas model” suits the needs of the Eastern part of Ukraine better than the Kyiv model.
Ukrainian president Petro Poroschenko is preparing to flee Ukraine. After the elections he would have to bear responsibility for corruption and infringements of the Ukrainian constitution.
No evidence given. Recurring pro-Kremlin narrative on Ukrainian elections, with emphasis put on alleged corruption and disruptions during the elections. See here for different pro-Kremlin narratives on Petro Poroshenko.